Screen wire stretching devices



D. J. COOK SCREEN WIRE STRETCHING DEVICES Dec. 6, 1960 Filed March 29, 1957 23 20 FIG.5

INVENTOR. DEL MERI C 00K IA IIII/IIII AIF 11 ATTORNEY The present invention relates to wire screen stretching devices, and has for an object to provide an improved stretching device of simple and inexpensive construction which will facilitate theapplication .of wire screen fabric to a frame in a smooth, taut condition.

Another object is to provide'a stretching device including screen clamping or gripping means automatically urged to clamping condition by displacement 'of the device in tensioning direction.

Ajfurther object is to provide a stretching device which will be retained on the frame while the stretched screen fabric is being fastened to the frame. 7 p

The invention further consis ts in the several features hereinafter described and claimed. p

In the accompanying drawing, illustrating certain enibodiments of the invention, I V A Fig. l is a top plan view of a stretching device of the invention as it appears in use in stretching wire screen fabric on a window frame; Fig. 2 is an enlarged fragmentary sectional view taken generally on the line 2 2 of Fig.1; Fig. 3 is a fragmentary sectional v ew of the device with the clamping members thereof in open position for receiving an edge portion of the screen fabric;

Fig. 4 is a sectional view, "similar to Fig. 2, showing a modified form of stretching device; m

Fig. 5 is a fragmentary top View of the stretching device of Fig. 4, and p Fig. 6 is a fragmentary sectional Viewof the device of Fig. 4 with the clamping membersthereof in open position for receiving an edge portion of the screen fabric.

Referring to the form of the invention shown in Figs. 1 to 3 of the drawing, the numeral "10 designates generally a stretching device of the invention, hereinafter more fully described, and the numeral 11 designates a rectangular frame, such as a window, frame or door frame, to which wire screen fabric 12 is to be secured in stretched or taut condition with the aid of the stretching device. The frame 11 includes the usual parallel side rails 13 and parallel upper and lower end rails 14 and 15, the latter having a flat bottom edge face 16 which in the case of a window frame is usually beveled to fit on a window sill. There is also shown suitable supporting means, such as a work bench 17, on which the screen frame 11 is laid in horizontal position for application of the screen fabric. taching operation is to be performed on a quantity production basis it is desirable to dispense the screen fabric from a roll 18, here shown to be rotatably and detachably supported on trunnions 19, the axis of rotation being parallel to the end rails of the frame. However, for occasional or infrequent use of the stretching device, as by householders and others, the roll need not be provided, and the frame may be supported in other ways, as on trestles or blocks, or even directly on a floor.

The stretching device 10 comprises a pair of elongated upper and lower clamping or gripping bars 20 and When the screen-at- V ICC 2 1, such as of heavy sheet metal, connected by a hinge 22 extending longitudinally of the bars along adjacent rear side edges of the bars. The hinge comprises curled knuckles 23 formed on the bars an'd'receivin'g a 'pintle rod 24. The clamping bars are longer than the width of the screen fabric 12 and will accommodate fabric of various widths. The lower clamping bar comprises a flat base portion 25 adapted to bear slidably on the upper flat face of the frame end rail 15 and has parallel upstanding flanges 26 and 27 along opposite longitudinal edges. The upper edge "of the flange 2'6 is connected by the hinge 22 to the upper clamping bar and places the hinge axis at a suitable elevation above the frame. At the edge opposite the hinge the upper "clamping bar has a 'downturned front flange or rib 28 which is adapted to overlap the upstanding front flange or rib 27 of the lower clamping bar to grip an edge portion of the screen fabric between them, and to bring the fabric close to the frame. If desired, the lower edge of the flange 28 may be serrated.

Rigidly secured to the upper clamping bar 20, as by welding, are spaced, rearwardly and downwatdly projec'ting arms 29 the free end or outer portions of which "are adapted to extend below the top plane of the window frame and have respective "end hubs 30 with respective screw-threaded bores 31 therethrough, the aires of these bores being parallel and normally horizontal. Parallel jack screws 32 are engaged in'the respective bored hubs 30 and each has a ball end '33 on which is swiveled a flat-faced clamping pad or shoe 34 adapted to abut against the beveled "edge face 16 of the frame. Each jack screw has a transversely apertured outer end head 35 receiving therethrough a headed slide handle '36 for turning the screw.

When the screen fabric 12 is to be applied to the frame 10, the frame is laid on the bench '17, as shown in Figs. 1 and 2, and a suitable length of the screen fabric is unrolled from the roll 18, the free end of the fabric extending a short distance over the inner edge portion of the frame end rail 15. The screen fabric is then attached to the face of the inner edge portion of the frame end rail 14, as by 'a row of staples 37 applied by a stapling gun, not shown. The screen fabric may then be severed along the stapled portion thereof on the line 38, Fig; l, or 'the'severingoperation maybe deferred until after the usual 'inolding strip 39, Fig. 2, is attached to the frame to cover the staples. The stretching device 10 is "slidably rested on the upper face or the frame end rail 15 in parallel relati'o'n'to this rail,'and the hinged clamping bars of the device are opened to admit the free end of the screen fabric, as shown in Fig. 3, the overhanging arms 29 tending to lift the clamping bar. The upper clamping bar is then manually depressed to grip the edge portion of the screen fabric between the gripping flanges or ribs 27 and 28, and while the upper bar is held down by one hand the jack screws 32 are rotated by the other hand to move the swiveled end pads 34 of the screws into frictional abutment with the edge face 16 of the frame rail 15 and to move the hingedly connected clamping bars outwardly for tensioning or stretching the screen fabric, the lower clamping bar 21 sliding on the upper face of the screen frame. The compression of the screen-tensioning jack screws exerts a turning force (clockwise in Fig. 2) on the arms 29 about the axis of the hinge22, thus urging the hinged upper clamping bar downwardly in clamping direction and holding the stretching device on the frame. During the 'screen-tensioning operation, the jack screws tend to tilt very slightly (clockwise in Fig. 2) on their ball ends 33. The frictional engagement of the screw end pads 34 with the edge face of the frame end rail will retain the stretching device "in clamped position, and this retaining action will be enhanced when the frame edge face 16 is beveled, as shown. The stretched end of the screen fabric is then fastened to the frame end rail 15, as by staples 49 applied by a stapling gun, not shown. The side edges of the screen fabric are similarly fastened to the side rails of the frame. If desired, tacks may be used instead of staples for fastening the screen fabric. The jack screws of the stretching device are then loosened, and the device is removed from the frame. The usual molding strips are then fastened over the stapled edges of the screen fabric. The narrow excess margin of the screen fabric is then trimmed off along the molding strip on the frame end rail 15.

The modified form of stretching device shown in Figs. 4 to 6 includes complementary upper and lower clamping bars 70 and 71, such as of hardwood. The vertical rear faces of the bars are of approximately equal width and are connected by spaced hinges 72 secured to the bars by screws 72'. The lower clamping bar 71 is of wedge-shaped cross-section tapering to a thin free edge opposite the hinged edge and has a flat bottom face 73 and an inclined top face 74. The lower portion of the upper clamping bar has a correspondingly inclined face 75. Near the thin edge of the lower clamping bar the inclined upper face 74 of this bar has a longitudinally extending screen-gripping rib or bead 76, and the lower face 75 of the upper bar has a complementary groove 77 adapted to receive the rib. In some instances the upper bar is provided with a row of nails 78 forming gripping teeth terminating in the groove 77 to engage the screen. It would also be possible to omit the rib 76 and groove and to rely on the gripping teeth and the clamping pressure of the bars.

A pair of spaced arms 79, generally similar to the arms 29 of Fig. 2, are secured to the upper face of the bar 70, as by screws 79, and carry respective ball-ended jack screws 32 with swivelled end clamping pads 34, as in Fig. 2, to engage the edge face 16 of the frame.

The stretching device 10' of Figs. 4 to 6 is used in the same manner as that of Figs. 1 to 3.

Each form of stretching device is of relatively simple and inexpensive construction and can readily be used by unskilled persons. The stretching device permits uniform and smooth stretching of the screen fabric in one operation, and the device will remain firmly in its set or tensioned condition while the gripped edges of the screen is stapled or otherwise fastened to the frame. The exposed portion of the screen fabric will not be damaged, and there is very little waste of screen material.

The stretching device can also be used on frames of the well-known type having rabbeted inner edges to receive the edges of the screen fabric, and on frames of the well-known type having spline-receiving grooves for attaching the screen fabric.

I claim:

1. A stretching device for use in applying wire screen fabric to a frame, comprising a first clamping bar adapted to be slidably supported on a face of the frame, a second clamping bar arranged in superposed parallel relation to said first bar and hingedly connected therewith about an axis extending longitudinally of said bars, said bars having cooperating gripping surfaces extending longitudinally of said bars forward of said axis, and said bars adapted to be urged together to grip between said surfaces an edge portion of the fabric, and stress-applying means operatively connected to said clamping bars and including arm means secured to said second clamping bar and jack screw means threadedly connected to said arm means and engageable with an edge of the frame for urging said hingedly connected bars together in fabricgripping relation and for displacing said bars along the face of the frame to stretch the gripped fabric.

2. A stretching device for use in applying wire screen fabric to a frame, comprising a first clamping bar adapted to be slidably supported on a face of the frame, a second clamping bar arranged in superposed parallel relation to said first bar and hingedly connected therewith about an axis extending longitudinally of said bars, said bars having cooperating gripping surfaces extending longitudinally of said bars forward of said axis, and said bars adapted to be urged together to grip between said surfaces an edge portion of the fabric, arm means rigidly secured to said second bar and having an outer portion extending rearwardly of said axis and below the plane of the first bar, and jack screw means having a threaded connection with the outer portion of said arm means and engaged with an edge of the frame for exerting downward fabric-gripping pressure on said second bar through said arm means and for displacing said hingedly connected fabric-gripping bars along the face of the frame to stretch the fabric.

3. A stretching device for use in applying wire screen fabric to a frame, comprising a first clamping bar adapted to be slidably supported on a face of the frame, a second clamping bar arranged in superposed parallel relation to said first bar and hingedly connected therewith about an axis extending longitudinally of said bars, said bars having cooperating gripping surfaces extending longitudinally of said bars forward of said axis, and said bars adapted to be urged together to grip between said surfaces an edge portion of the fabric, the hinge axis of said bars being at a higher elevation than the fabric-gripping surfaces of said bars, and stress-applying means operatively connected to said clamping bars and including arm means secured to said second clamping bar and jack screw means threadedly connected to said arm means and engageable with an edge of the frame for urging said hingedly connected bars together in fabric-gripping relation and for displacing said bars along the face of the frame to stretch the gripped fabric.

4. A stretching device for use in applying wire screen fabric to a frame, comprising a first clamping bar adapted to be slidably supported on a face of the frame and having an upwardly projecting rib extending longitudinally of the bar adajcent to the forward edge of the bar, a second clamping bar extending longitudinally above said first bar and movably connected therewith for downward displacement, said second bar having a downwardly projecting rib extending longitudinally of said second bar adjacent to the forward edge of said bar and adapted to lap said first rib for gripping an edge portion of the fabric between said ribs, and stress-applying means operatively connected to said clamping bars and including arm means secured to said second clamping bar and jack screw means threadedly connected to said arm means and adapted to engage an edge of the frame for urging said second bar downwardly to grip the fabric between said ribs and for displacing said bars along the face of the frame to stretch the gripped fabric.

5. A stretching device for use in applying wire screen fabric to a frame, comprising a first clamping bar adapted to be slidably supported on a face of the frame and having an upwardly projecting marginal rib extending longitudinally of the bar adjacent to the forward edge of the bar, a second clamping bar extending longitudinally above said first bar and movably connected therewith for downward displacement, said second bar having a downwardly projecting rib extending longitudinally of said second bar adjacent to the forward edge of said bar and adapted tolap said first rib for gripping an edge portion of the fabric between said ribs, and stress-applying means operatively connected to said clamping bars and including arm means secured to said second clamping bar and jack screw means threadedly connected to said arm means and adapted to engage an edge of the frame for urging said second bar downwardly to grip the fabric between said ribs and for displacing said bars along the face of the frame to stretch the gripped fabric, the rib on said second bar being forward of said first bar for pressing the fabric downwardly toward the face of the frame.

6. A stretching device for use in applying wire screen fabric to a frame, comprising a first clamping bar adapted to be slidably supported on a face of the frame, a second clamping bar extending longitudinally above said first bar and hingedly connected therewith about an axis extending longitudinally of said bars at adjacent rear side portions of the bars, said bars having confronting fabricgripping surfaces adjacent to the front side portions of the bars opposite the hinge connection, said first bar being of wedge-shaped cross section convergent from the hinged side portion toward the fabric-gripping side portion, arm means rigidly secured to said second bar and having an outer portion extending rearwardly of said bar and below the bottom plane of said first bar, and jack screw means having a threaded connection with the outer portion of said m means and engageable with an edge of the 5 2,693,205

References Cited in the file of this patent UNITED STATES PATENTS 324,673 Ehrenfeld Aug. 18, 1885 738,421 Distelhurst Sept. 8, 1903 1,156,597 Hanson Oct. 12, 1915 1,273,074 La Roe July 16, 1918 2,216,880 Floyd Oct. 8, 1940 2,588,501 Dummer Mar. 11, 1952 Coulter ....--V Nov. 2, 1954 

